Nuclear Physics A485 (1988) 16-30 North-Holland, Amsterdam STUDY OF THE POTENTIAL ENERGY OF "OCTUPOLE"-DEFORMED NUCLEI IN A MULTIDIMENSIONAL DEFORMATION SPACE Adam SOBICZEWSKI and Zygmunt PATYK Institute for Nuclear Studies, Hoza 69, PL-00-681 Warszawa, Poland Stefan CWIOK Instttute of Physics, Warsaw Techmcal University, PL-00-622 Warszawa, Poland Plotr ROZMEJ i GSI, D-6100 Darmstadt, F R Germany Received 7 December 1987 Abstract: The collectwe potentml energy of even-even "octupole'-deformed nuclei is studied m a multidimensional deformation space m both radium and barium regions This energy is calculated by the macroscopic-microscopic method, with the Yukawa-plus-exponentml model taken for the macroscopic part and the Strutmski shell correction (based on the Woods-Saxon single-particle potentml) used for the mmcroscoplc part of the energy The deformations fla of all multlpolanty degrees A = 2, 3, ,7 (or even 8) are treated as independent variables The mulilpolantles A = 5, 6 and 7, usually omitted or treated in an average way up to now, are found to be important for the properties of the nuclei I. Introduction It has been known for some time that specific properties of nuclei around radium suggest that these nuclei have an octupole deformation (see e g the review papers 1-3)). More recent theoretical calculations of the potential energy of these nuclei give minima at octupole deformations different from zero (e.g. refs. 4-9)). However, the values of the deformations, the deformation energies and especially the octupole-barrier heights (i.e. the gain in energy of a nucleus due to its octupole deformation) differ from one calculation to another. One of the reasons for these differences in the results is different treatment of the nuclear deformation. Instead of treating the deformation of each multipolarlty as an independent variable, some combinations of the various multlpolarltles have been taken 5), to simplify the calculations The deformations of multipolarsty higher than 4 have been, as a rule, omitted or treated only in an average way 6.7) as deduced from the study of the macroscopic part and not of the total energy Sometimes, it has also been the case that a higher multipolarlty (e.g A --6) has been taken into account whde a lower one (e.g. A = 5) has not All this resulted in a rather restricted deformation space, imposing on it rather artificial constraints. 1 On leave from the Institute of Physics, University MCS, PL-20-031 Lubhn, Poland 0375-9474/88/$03 50 ~) Elsevier Science Pubhshers B V (North-Holland Physics Publishing Division)